fix(naming): rename option to skip merge files

[fnareoh]

Context

I failed and forgot to push my changes to the naming :facepalm:

What has been done

Validation

PR check list

• [ ] As much as possible, the changes include tests (unit and/or functional)
• [ ] If the changes affect the end user (new feature, behavior change, bug fix) then the PR has a changelog entry (see doc/dev/getting-started.md). If the changes do not affect the end user, then the skip-changelog label has been added to the PR.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 91.54%. Comparing base (c3b3b62) to head (ef76847). Report is 10 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #955 +/- ## ======================================= Coverage 91.54% 91.54% ======================================= Files 178 178 Lines 7372 7372 ======================================= Hits 6749 6749 Misses 623 623 ``` | [Flag](https://app.codecov.io/gh/GitGuardian/ggshield/pull/955/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=GitGuardian) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/GitGuardian/ggshield/pull/955/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=GitGuardian) | `91.54% <ø> (ø)` | | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=GitGuardian#carryforward-flags-in-the-pull-request-comment) to find out more.

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